Abstract: The present invention relates to an apparatus for aligning a sensor relative to at least two anatomical reference points of a patient's anatomy. In one embodiment, the apparatus includes: a body having a central axis; a sensor mount positioned relative to the body; at least two arms extending from the body, wherein two of said at least two arms are simultaneously and equidistantly moveable relative to the central axis; and at least two aligners connected to the at least two arms for aligning with said at least two anatomical reference points. The apparatus may also include an apparatus sensor. The present invention also relates to a surgical system for monitoring the orientation of a patient's anatomy, which includes the apparatus. Furthermore, the present invention also relates to a surgical system for guiding a surgical device to an optimal orientation relative to a patient's anatomy, wherein the surgical system includes the apparatus.